Underground grouting method for blocking lateral burning rock water space

Abstract

The application provides a downhole grouting method for plugging a water-conducting space of laterally burned rock, comprising the following steps: determining a water-conducting space of laterally burned rock of a coal seam and a working face to be mined in the coal seam affected by the water-conducting space, and drawing a curtain line of the water-conducting space outside a mining disturbance damage range of the working face to be mined; arranging a plurality of first grouting holes between the curtain line and the burned rock, grouting the first grouting holes, and determining diffusion ranges of slurries with different concentrations; determining a slurry concentration corresponding to a second grouting hole and a diffusion range of a slurry corresponding to the slurry concentration, determining a spacing of the second grouting hole according to the diffusion range of the slurry corresponding to the slurry concentration; arranging a plurality of second grouting holes between the curtain line and the burned rock according to the spacing of the second grouting hole, and grouting the second grouting holes from the working face to be mined according to the slurry concentration corresponding to the second grouting hole. The application improves the accuracy of grouting plugging, reduces the grouting time, saves the amount of grouting slurry, and reduces the grouting cost.

Description

Technical Field

[0001] This invention relates to the field of mine water control technology, and in particular to an underground grouting method for sealing the water-conducting space of lateral sintered rock. Background Technology

[0002] The phenomenon of coal seam ignition occurs because the coal seam outcrops are shallow and the surface gullies are well-developed. When the coal seam spontaneously combusts at the exposed area after being cut by the gullies, a burned area is formed. After the coal seam collapses due to combustion, forming the burned area, the internal fissures of the entire ignition rock are highly developed. When there is water in the vicinity of the ignition rock, such as a reservoir, lake, river, or other aquifers, the fissures of the ignition rock will fill with water, becoming a strong aquifer. Some ignition rock aquifers have even become important water sources for some areas.

[0003] Coal combustion is not always complete, and there may still be recoverable coal resources on the side of the ignited coal seam. However, if the coal resources on the side of the ignited rock are planned for recovery, the ignited rock may become a water source, threatening mine safety and normal production, and wasting groundwater resources. To prevent water from the ignited rock in the same coal seam from entering the mine's extraction system, a lateral seepage barrier wall needs to be constructed in the ignited rock strata to artificially separate the ignited rock aquifer from the planned coal resources. Extraction can only proceed after ensuring that the ignited rock aquifer is not disturbed during the coal seam extraction process.

[0004] The development of fissures in sintered rock provides a basis for the feasibility of grout diffusion and flow. The key to constructing a water-tight curtain through grouting is that the grout between the grouting holes can interconnect and overlap, blocking the water passages in the fissures of the sintered rock and forming an integral water-tight structure. In the grouting process targeting the aquifer of sintered rock in the same coal seam, it is required that the water-tight wall formed by grouting accurately and specifically seals the fissures in the sintered rock to prevent some fissure channels from being incompletely sealed, thus failing to achieve the expected water-tightening effect. This would lead to the expansion of the fissure channels after coal mining, ultimately destroying the grouting effect.

[0005] Currently, the main method for curtain grouting of sintered rock aquifers is surface curtain grouting. This method is primarily used for curtain grouting of sintered rock aquifers overlying or beneath the coal seam from the surface. Surface curtain grouting is carried out on the ground, which makes site acquisition difficult. Furthermore, surface grouting is located far from the coal seam, resulting in high grouting costs and relatively low accuracy. Summary of the Invention

[0006] This invention provides a downhole grouting method for sealing the water-conducting space of lateral sintered rock, which solves the defects of existing surface curtain grouting construction sites such as difficulty in acquiring sites, high grouting costs, and low accuracy. It achieves rapid downhole grouting in a local area with a small construction range, short construction time, low construction cost, and high accuracy.

[0007] This invention provides a downhole grouting method for blocking the water-conducting space of laterally sintered rock, comprising:

[0008] Determine the water-conducting space of the sintered rock on the side of the coal seam and the working face to be mined in the coal seam affected by the water-conducting space, and delineate the curtain line of the water-conducting space outside the mining disturbance and damage range of the working face to be mined.

[0009] Multiple first grouting holes are arranged between the curtain line and the sintered rock, and grouting is performed on the first grouting holes to determine the diffusion range of grout of different concentrations.

[0010] Determine the grout concentration corresponding to the second grouting hole and the diffusion range of the grout corresponding to the grout concentration, and determine the spacing of the second grouting holes based on the diffusion range of the grout corresponding to the grout concentration;

[0011] Multiple second grouting holes are arranged between the curtain line and the sintered rock according to the spacing of the second grouting holes. Grouting is injected from the working face to be mined into the second grouting holes according to the grout concentration corresponding to the second grouting holes.

[0012] According to the present invention, a downhole grouting method for blocking laterally sintered rock water-conducting spaces includes the following steps: grouting the first grouting hole and determining the diffusion range of grouts of different concentrations.

[0013] Grouting is performed sequentially into the middle grouting hole among the plurality of first grouting holes, in order of increasing concentration;

[0014] The diffusion range of grout of different concentrations is determined based on whether the grout from the intermediate first grouting hole permeates into the other first grouting holes besides the intermediate first grouting hole, and the distance between the intermediate first grouting hole and the other first grouting holes.

[0015] According to the present invention, a downhole grouting method for plugging lateral water-conducting spaces in sintered rock includes the step of determining the grout concentration corresponding to the second grouting hole as follows:

[0016] Based on the groundwater flow velocity between the curtain line and the sintered rock, the grout concentration of the second grouting hole corresponding to the groundwater flow velocity is determined; wherein the groundwater flow velocity and the grout concentration are pre-correlated.

[0017] According to the present invention, a downhole grouting method for blocking the water-conducting space of lateral sintered rock is provided, wherein the second grouting hole passes through the top fresh bedrock and the bottom fresh bedrock of the sintered rock.

[0018] According to the present invention, a downhole grouting method for blocking the water-conducting space of lateral sintered rock is provided, wherein the depths of the plurality of second grouting holes are different;

[0019] The step of injecting grout from the working surface to be mined into the second grouting hole according to the grout concentration corresponding to the second grouting hole includes:

[0020] When there is water in the second grouting hole, the second grouting hole is grouted in order of increasing depth according to the grout concentration corresponding to the second grouting hole.

[0021] The final grouting pressure varies depending on the depth of the second grouting hole; the greater the depth of the second grouting hole, the greater the final grouting pressure.

[0022] According to the present invention, a downhole grouting method for plugging lateral water-conducting spaces in sintered rock includes the step of grouting from the working face to be mined into the second grouting hole according to the grout concentration corresponding to the second grouting hole, comprising:

[0023] When the groundwater flow velocity at the second grouting hole is less than the first preset threshold, single-component cement slurry is injected into the second grouting hole;

[0024] When the groundwater flow velocity at the second grouting hole is greater than or equal to the first preset threshold, the single-component cement grout and the two-component grout of cement and water glass are injected into the second grouting hole.

[0025] Expandable chemical grout is injected into the water-conducting cracks in the water-conducting space through the second grouting hole.

[0026] According to the present invention, a downhole grouting method for blocking the water-conducting space of lateral sintered rock is provided, wherein a coagulant is added to the single-liquid cement grout.

[0027] According to the present invention, a downhole grouting method for blocking the water-conducting space of lateral sintered rock is provided, wherein the water-cement ratio in the single-liquid cement grout ranges from 0.5:1 to 1.25:1.

[0028] According to the present invention, a downhole grouting method for plugging the water-conducting space of lateral sintered rock, after the step of grouting from the working face to be mined into the second grouting hole according to the grout concentration corresponding to the second grouting hole, further includes:

[0029] Drilling was conducted to expose the burnt rock within the mining disturbance and damage range of the working face to be mined;

[0030] If water continues to emerge during drilling and the water volume remains constant, then supplementary grouting should be performed on the second grouting hole corresponding to the drilling location.

[0031] According to the present invention, a downhole grouting method for plugging the water-conducting space of lateral sintered rock, after the step of grouting from the working face to be mined into the second grouting hole according to the grout concentration corresponding to the second grouting hole, further includes:

[0032] Determine the attenuation value of water volume, the attenuation value of water pressure, and the water volume at the observation hole of the working face to be mined;

[0033] If the decrease in water volume or water pressure is less than a second preset threshold, or if the decrease in water volume is greater than a third preset threshold, a third grouting hole is added between the second grouting holes, and grouting is performed on the third grouting hole.

[0034] The downhole grouting method for sealing the water-conducting space of lateral sintered rock provided by this invention delineates a curtain line based on the relative position of the water-conducting space and the working face to be mined. Grouting holes are then arranged on the side of the curtain line away from the working face to ensure that the grouting holes are not damaged by the working face. Test holes are used to determine the diffusion range of the grout concentration injected into the grouting holes, thereby determining the spacing of the grouting holes and ensuring that the area between the second grouting holes is permeable to the grout, forming a water-proof wall and ensuring the water-proofing effect. Grouting is performed from the downhole working face to the grouting holes, which improves the accuracy and efficiency of grouting, reduces the amount of grout used, and lowers the grouting cost. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a schematic flowchart of the downhole grouting method for sealing the water-pouring space in laterally sintered rock provided by the present invention;

[0037] Figure 2 This is a schematic diagram of the cross-section of the lateral sintered rock curtain grouting project in the downhole grouting method for sealing the lateral sintered rock water inflow space provided by the present invention;

[0038] Figure 3 This is a schematic diagram of the downhole curtain grouting cross-section in the downhole grouting method for sealing the water-pouring space of lateral sintered rock provided by the present invention;

[0039] Figure 4 This is a schematic cross-sectional view of the grouting borehole in the downhole grouting method for sealing the water-pouring space of lateral sintered rock provided by the present invention.

[0040] Figure label:

[0041] 1: Working face to be mined; 2: Working face roadway; 3: Working face cut; 4: Shallow grouting hole; 5: Deep grouting hole; 6: Water guiding space; 7: Burned rock; 8: Burned rock boundary line; 9: Coal seam roof mudstone; 10: Coal seam floor mudstone; 11: Coal seam roof sandstone; 12: Neogene laterite layer; 13: Quaternary loose layer; 14: Coal seam floor sandstone; 15: Adjacent working face; 16: No. 3 coal seam; 17: Observation hole. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0043] The following is combined with Figures 1 to 4 This invention describes an underground grouting method for sealing lateral water-conducting spaces in sintered rock. By grouting underground, a water-stop curtain is formed between the working face and the sintered rock, preventing water storage in the sintered rock from affecting coal mining operations. The method includes:

[0044] Step 101: Determine the water-conducting space of the sintered rock on the side of the coal seam and the working face to be mined in the coal seam affected by the water-conducting space, and delineate the curtain line of the water-conducting space outside the mining disturbance and damage range of the working face to be mined.

[0045] Based on the results of geophysical exploration and drilling, the upper and lower boundaries and horizontal range of the water-conducting space 6 were determined, thereby determining the water-conducting space of the pyromorphic rock 7.

[0046] There are usually multiple working faces 1 to be mined in coal mining. Based on the spatial relationship between the water-conducting space and each working face 1 to be mined, the working faces to be mined in the coal seam that are affected by the water-conducting space are determined.

[0047] like Figure 2 In the process, since the distance between the working face 1 to be mined and the boundary line 8 of the burnt rock is relatively close, the water-conducting space 6 extends into the working face 1 to be mined. Therefore, the working face 1 to be mined is affected by the water-conducting space 6 and needs to be grouted to isolate water.

[0048] The distance between the adjacent working face 15 and the boundary line 8 of the igneous rock of the working face 1 to be mined is relatively far, and the water-conducting space 6 does not extend into the adjacent working face 15. Therefore, the adjacent working face 15 is not affected by the water-conducting space 6 and does not require grouting for water isolation. The working face roadway 2 between the working face 1 to be mined and the adjacent working face 15 is used for the passage of personnel between the working faces.

[0049] The curtain line of the water-conducting space 6 is used to determine the grouting range, thereby cutting off the water-conducting space 6 in the horizontal direction. Since the grouting water-blocking wall will be damaged within the mining disturbance and destruction range of the working face to be mined, thus affecting the water-conducting effect, the curtain line is drawn outside the mining disturbance and destruction range of the working face to be mined. Figure 2 The curtain line is located inside the grouting shallow hole 4 and is parallel to the grouting shallow hole 4.

[0050] like Figure 3 As shown, the ignited rock 7 and the working face 1 are located in the same No. 3 coal seam 16. This coal seam has a simple structure, a small dip angle, and is a near-horizontal coal seam with an average thickness of approximately 10m. Due to spontaneous combustion of No. 3 coal seam 16, the spontaneously combusted coal seam and the baked surrounding rock form ignited rock. Due to its special mechanism, it becomes a good water storage space, and the ignited rock aquifer becomes the main source of water inflow in some areas. In order to achieve water-conserving mining, local grouting is carried out underground according to the working face layout and hydrogeological conditions.

[0051] Figure 3 The strata in the grouting work area, from the No. 3 coal seam 16 mined from the working face upwards, are successively the coal seam roof mudstone 9, coal seam roof sandstone 11, Neogene laterite layer 12 and Quaternary loose layer 13, and downwards successively the coal seam floor mudstone 10 and coal seam floor sandstone 14.

[0052] Step 102: Arrange multiple first grouting holes between the curtain line and the sintered rock, grout the first grouting holes, and determine the diffusion range of grout of different concentrations.

[0053] The first grouting hole is a test hole. To determine the spacing of the grouting holes for waterproofing, test holes are first established. Grout of different concentrations is injected into the test holes sequentially, and the diffusion range of the grout of different concentrations is observed. The spacing between the grouting holes for waterproofing is then determined based on the diffusion range.

[0054] Optionally, multiple first grouting holes are arranged at equal intervals along the curtain line, with the spacing between the first grouting holes generally ranging from 6 to 12 meters.

[0055] Step 103: Determine the grout concentration corresponding to the second grouting hole and the diffusion range of the grout corresponding to the grout concentration, and determine the spacing of the second grouting holes based on the diffusion range of the grout corresponding to the grout concentration.

[0056] The second grouting hole is a water-tight grouting hole. Optionally, the concentration of the grout to be injected into the second grouting hole is determined based on the water content of different areas between the curtain line and the igneous rock; the higher the water content, the higher the concentration. This embodiment does not limit the method for determining the grout concentration corresponding to the second grouting hole.

[0057] Based on the experimental results of the first grouting hole, the diffusion range of the grout concentration corresponding to the second grouting hole is determined, thereby obtaining the spacing of the second grouting hole.

[0058] Step 104: According to the spacing of the second grouting holes, multiple second grouting holes are arranged between the curtain line and the sintered rock, and grout is injected into the second grouting holes according to the grout concentration corresponding to the second grouting holes.

[0059] The spacing between the second grouting holes is less than or equal to the diffusion range of the grout concentration corresponding to the second grouting hole, thereby ensuring that the area between the second grouting holes is permeable to grout, forming a water-proof wall and ensuring the water-proof effect.

[0060] like Figure 2 In the middle, two rows of second grouting holes parallel to the curtain line are arranged between the curtain line and the burnt rock, namely grouting shallow hole 4 and grouting deep hole 5.

[0061] The spacing between each row of holes is between 9 and 15 meters, depending on the diffusion range of the grout. Curtain grouting severs the hydraulic connection between the working face to be mined and the calcined rock of the same coal seam.

[0062] Optionally, the second grouting holes combine deep and shallow holes, and from the cross-sectional view, the holes are arranged in a quincunx pattern. The second grouting holes are grouted in order of increasing grout concentration.

[0063] Before grouting, cement ash is transported underground and mixed with water to form a grouting slurry. The prepared slurry is then... Figure 2 The working face cut-out 3 in the middle is used to grout the first and second grouting holes downhole, which effectively reduces the length of the grouting channel, improves the accuracy of grouting, and reduces the cost of grouting.

[0064] In this embodiment, the curtain line is defined by the relative position of the water guiding space and the working face to be mined. Grouting holes are arranged on the side of the curtain line away from the working face to ensure that the grouting holes are not damaged by the working face. Test holes are used to determine the diffusion range of the grout concentration injected into the grouting holes, thereby determining the spacing of the grouting holes to ensure that the area between the second grouting holes is permeable with grout, forming a water-proof wall and ensuring the water-proof effect. Grouting is performed from the working face downhole into the grouting holes, which improves the accuracy and efficiency of grouting, reduces the amount of grout used, and lowers the grouting cost.

[0065] Based on the above embodiments, the step of grouting the first grouting hole and determining the diffusion range of grout of different concentrations in this embodiment includes: grouting the middle first grouting hole in the plurality of first grouting holes in order of increasing concentration;

[0066] The diffusion range of grout of different concentrations is determined based on whether the grout from the intermediate first grouting hole permeates into the other first grouting holes besides the intermediate first grouting hole, and the distance between the intermediate first grouting hole and the other first grouting holes.

[0067] When testing the diffusion range of grouts of different concentrations, the first grouting hole located in the middle position is selected for grouting. After grouting is completed, multiple other first grouting holes around the first grouting hole are inspected to determine whether grout has spread into the hole, thereby determining the diffusion range of the grout.

[0068] If necessary, additional holes can be added between the first grouting holes or outwards to ensure that the diffusion radius of grouts of different concentrations is clearly defined.

[0069] Meanwhile, if a test grout with a higher concentration is performed first, the grout may affect the diffusion results of the subsequent grout with a lower concentration. Therefore, the grouting work is carried out on the first grouting hole in order of increasing grout concentration.

[0070] Based on the above embodiments, the step of determining the grout concentration corresponding to the second grouting hole in this embodiment includes: determining the grout concentration of the second grouting hole corresponding to the groundwater flow velocity based on the groundwater flow velocity between the curtain line and the sintered rock; wherein the groundwater flow velocity and the grout concentration are pre-correlated.

[0071] The faster the groundwater flow rate, the higher the grout concentration in the second grouting hole; the slower the groundwater flow rate, the lower the grout concentration in the second grouting hole, thus enabling the grout to solidify effectively and ensuring the water-proof effect.

[0072] Based on the above embodiments, in this embodiment, the second grouting hole penetrates the top fresh bedrock and the bottom fresh bedrock of the sintered rock.

[0073] The top and bottom fresh bedrock of the igneous rock form the bedrock on both sides of the boundary line of the water-conducting space of the igneous rock. When grouting the second grouting holes to form a water-blocking wall, each second grouting hole passes through the top and bottom fresh bedrock of the igneous rock, thereby forming a stable water-blocking structure at the boundary of the igneous rock and improving the water-blocking effect.

[0074] Based on the above embodiments, the depths of the multiple second grouting holes in this embodiment are different.

[0075] The step of injecting grout from the working surface to be mined into the second grouting hole according to the grout concentration corresponding to the second grouting hole includes:

[0076] When there is water in the second grouting hole, the second grouting hole is grouted in order of increasing depth according to the grout concentration corresponding to the second grouting hole.

[0077] The final grouting pressure varies depending on the depth of the second grouting hole; the greater the depth of the second grouting hole, the greater the final grouting pressure.

[0078] When grouting the second grouting holes at different depths, it is necessary to determine whether there is water inside the second grouting hole. Grouting should only be carried out if water is found. Otherwise, grouting will increase the pressure inside the hole and fail to meet the grouting conditions.

[0079] Based on the grout concentration corresponding to the second grouting hole, the second grouting holes are grouted sequentially in order of increasing depth.

[0080] The final grouting pressure varies depending on the depth of the second grouting hole. The final pressure for shallow holes is usually 1 to 2 MPa, to avoid breaking through the roadway and causing grout leakage; the final grouting pressure for medium-deep holes should reach 3 to 5 MPa; and the final grouting pressure for deep holes can reach more than 8 MPa to achieve the effect of splitting and compacting, so that the stone body does not shrink excessively during consolidation and water seepage, thus creating new cracks that affect the grouting and water-blocking effect.

[0081] The final pressure of grouting can be flexibly adjusted based on the results of on-site grouting tests, and is not limited to the range listed above.

[0082] Based on the above embodiments, the step of grouting the working surface to be mined from the second grouting hole according to the grout concentration corresponding to the second grouting hole in this embodiment includes: injecting single-component cement grout into the second grouting hole when the groundwater flow velocity at the second grouting hole is less than a first preset threshold.

[0083] Optionally, the first preset support is 25 m / h. When the groundwater flow velocity is less than 25 m / h, single-component cement grout is used to grout the second grouting hole.

[0084] When the groundwater flow velocity is greater than or equal to the first preset threshold, single-component cement grout and a two-component grout consisting of cement and water glass are injected into the second grouting hole.

[0085] When the groundwater flow velocity is greater than or equal to 25 m / h, considering the cost and diffusion effect of the grout, grouting is still mainly carried out with single-component cement grout. At the same time, for areas with unobstructed water-conducting fissures and grout leakage on the surface of the tunnel, cement and water glass dual-component grout is appropriately used to seal the channels to ensure the grouting effect.

[0086] Expandable chemical grout is injected into the water-conducting cracks in the water-conducting space through the second grouting hole;

[0087] Injecting an expansive chemical grout into the water-conducting cracks formed by the spread of thermal energy is used to displace the water in the water-conducting space and seal the small cracks.

[0088] Expandable chemical slurries include, but are not limited to, urea-formaldehyde resin or epoxy resin organic polymer water-blocking materials.

[0089] Based on the above embodiments, a coagulant is added to the single-liquid cement slurry in this embodiment.

[0090] Optionally, the coagulant is a triethanolamine-sodium chloride quick-setting and early-strength agent, or other coagulants with quick-setting and early-strength effects, used to improve the strength of cement after setting.

[0091] Based on the above embodiments, the water-cement ratio in the single-component cement slurry in this embodiment ranges from 0.5:1 to 1.25:1.

[0092] The specific values ​​can be selected based on the grouting range and grouting effect obtained during the trial grouting process. If necessary, the ratio can be lower than 0.5:1 or higher than 1.25:1.

[0093] Under normal circumstances, silicate cement with a P.O42.5 or higher should be selected as the main material for grouting.

[0094] Based on the above embodiments, this embodiment further includes, after the step of injecting grout into the second grouting hole according to the grout concentration corresponding to the second grouting hole, drilling to reach the burnt rock within the mining disturbance and damage range of the working face; if water continues to emerge during the drilling process and the water volume remains unchanged, then supplementary grouting is performed on the second grouting hole corresponding to the drilling location.

[0095] After grouting is completed, borehole exploration is carried out on the sintered rock within the mining disturbance and damage range of the working face to be mined, forming... Figure 2 Observation hole 17 in the middle.

[0096] If water continues to flow during drilling and the water volume remains constant, it indicates that there are gaps in the water-resistant wall formed by grouting, and the second grouting hole should be filled with grout.

[0097] Based on the above embodiments, this embodiment further includes, after the step of injecting grout into the second grouting hole according to the grout concentration corresponding to the second grouting hole, determining the attenuation value of the water volume, the attenuation value of the water pressure, and the water volume in the second grouting hole;

[0098] Reference Figure 2 After the initial grouting is completed, the water volume decay value, water pressure decay value and water volume are measured through the observation hole 17 reserved before grouting, and the grouting effect is determined by measuring the water volume and water pressure decay value.

[0099] If the decrease in water volume or water pressure is less than the second preset threshold, or if the decrease in water volume is greater than the third preset threshold, a third grouting hole is added between the second grouting holes, and grouting is performed on the third grouting hole.

[0100] Optionally, the second preset threshold is 75%, and the third preset threshold is 15m. 3 / h, meaning when the decrease in water pressure or water volume is less than 75%, or the water volume is greater than 15m³. 3In the case of / h, a third grouting hole needs to be drilled around the second grouting hole, and grouting is performed on the third grouting hole to further enhance the grouting effect until the attenuation values ​​of water volume and water pressure are both greater than or equal to the second preset threshold, and the water volume is less than or equal to the third preset threshold.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A downhole grouting method for sealing lateral water-conducting spaces in sintered rock, characterized in that, include: Determine the water-conducting space of the sintered rock on the side of the coal seam and the working face to be mined in the coal seam affected by the water-conducting space, and delineate the curtain line of the water-conducting space outside the mining disturbance and damage range of the working face to be mined. Multiple first grouting holes are arranged between the curtain line and the sintered rock. Grouting is performed on the first grouting holes to determine the diffusion range of grout of different concentrations. The first grouting holes are test holes. Determine the grout concentration corresponding to the second grouting hole and the diffusion range of the grout corresponding to the grout concentration, and determine the spacing of the second grouting holes based on the diffusion range of the grout corresponding to the grout concentration; Multiple second grouting holes are arranged between the curtain line and the sintered rock according to the spacing of the second grouting holes, and grout is injected from the working surface to be mined into the second grouting holes according to the grout concentration corresponding to the second grouting holes; The step of determining the grout concentration corresponding to the second grouting hole includes: Based on the groundwater flow velocity between the curtain line and the sintered rock, the grout concentration of the second grouting hole corresponding to the groundwater flow velocity is determined; wherein, the groundwater flow velocity and the grout concentration are pre-correlated. The groundwater flow velocity is positively correlated with the grout concentration in the second grouting hole; The step of grouting the first grouting hole and determining the diffusion range of grouts of different concentrations includes: Grouting is performed sequentially into the middle grouting hole among the plurality of first grouting holes, in order of increasing concentration; The diffusion range of grout of different concentrations is determined based on whether the grout from the intermediate first grouting hole permeates into the other first grouting holes besides the intermediate first grouting hole, and the distance between the intermediate first grouting hole and the other first grouting holes.

2. The downhole grouting method for sealing the water-conducting space of laterally ignited rock according to claim 1, characterized in that, The second grouting hole penetrates the top fresh bedrock and the bottom fresh bedrock of the igneous rock.

3. The downhole grouting method for sealing the water-conducting space of laterally ignited rock according to claim 1, characterized in that, The depth of the second grouting hole is different; The step of injecting grout from the working surface to be mined into the second grouting hole according to the grout concentration corresponding to the second grouting hole includes: When there is water in the second grouting hole, the second grouting hole is grouted in order of increasing depth according to the grout concentration corresponding to the second grouting hole. The final grouting pressure varies depending on the depth of the second grouting hole; the greater the depth of the second grouting hole, the greater the final grouting pressure.

4. The downhole grouting method for sealing the water-conducting space of laterally ignited rock according to claim 1, characterized in that, The step of injecting grout from the working surface to be mined into the second grouting hole according to the grout concentration corresponding to the second grouting hole includes: When the groundwater flow velocity at the second grouting hole is less than the first preset threshold, single-component cement slurry is injected into the second grouting hole; When the groundwater flow velocity at the second grouting hole is greater than or equal to the first preset threshold, the single-component cement grout and the two-component grout of cement and water glass are injected into the second grouting hole. Expandable chemical grout is injected into the water-conducting cracks in the water-conducting space through the second grouting hole.

5. The downhole grouting method for sealing the water-conducting space of laterally ignited rock according to claim 4, characterized in that, A coagulant is added to the single-component cement slurry.

6. The downhole grouting method for sealing the water-conducting space of laterally ignited rock according to claim 4, characterized in that, The water-cement ratio in the single-component cement slurry ranges from 0.5:1 to 1.25:

1.

7. The downhole grouting method for sealing the water-conducting space of laterally ignited rock according to claim 1, characterized in that, After the step of grouting the working surface to be mined from the second grouting hole according to the grout concentration corresponding to the second grouting hole, the method further includes: Drilling was conducted to expose the burnt rock within the mining disturbance and damage range of the working face to be mined; If water continues to emerge during drilling and the water volume remains constant, then supplementary grouting should be performed on the second grouting hole corresponding to the drilling location.

8. The downhole grouting method for sealing the water-conducting space of laterally ignited rock according to claim 1, characterized in that, After the step of grouting the working surface to be mined from the second grouting hole according to the grout concentration corresponding to the second grouting hole, the method further includes: Determine the attenuation value of water volume, the attenuation value of water pressure, and the water volume at the observation hole of the working face to be mined; If the decrease in water volume or water pressure is less than a second preset threshold, or if the decrease in water volume is greater than a third preset threshold, a third grouting hole is added between the second grouting holes, and grouting is performed on the third grouting hole.

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